Independently of the fact nothing was changed in the 6.11.1 concerning the context menu of a class, for me all is ok

Having that configuration :

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The creation of the source artifact is proposed at class level when the container class view has an associated deployment view and of course when the class is not already managed by an artifact (scroll the image if needed to see the menu entry) :

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May be you are in a case where the container class view doesn't have an associated deployment view like that :